ANNAPOLIS, MD (March 1, 2018) – In the last week of January 2018, one of a pair of free-ranging pigs (Sus scrofa) attacked and bit a citizen in Frederick County, Maryland. The porcine perpetrator was subsequently killed by Frederick County Animal Control for rabies testing, which fortunately was negative. The event, and a photograph of a large swine with formidable tusks, got people buzzing: are there wild pigs in Maryland? This recent run-in prompted the Maryland Invasive Species Council to choose the feral swine as the March Invader of the Month.

While known by many names (wild boar, razorback, wild hog, Russain or Eurasion boar, feral pig), all swine are the same species (Sus scrofa), and domesticated hogs living in the wild quickly make a remarkable regression to a more primitive and formidable ancestral type. When feral swine run wild in a natural landscape, their digging and the removal of native vegetation disturb and degrade ecosystems, and often introduce disturbance-seeking invasive plant species. Maryland has no known viable populations of feral swine, but there are populations in the surrounding states of Virginia, West Virginia, and Pennsylvania. The swine that attacked the gentleman in Frederick County may have migrated down the Appalachian ridges from Pennsylvania or could have had a more local origin. Feral swine populations can be started by escaped livestock or pets.

Sus scrofa that range freely as feral pigs maintain an appearance similar to domestic forms or the wild European boar, though their hides become thicker, their tusks elongate, and they are often more slender. They have any average weight between 75-250 pounds but can be much larger as well. Colors and patterns vary widely between white, black, brown, and red. Piglets typically have spots or stripes. Once mature, they can be up to three feet tall and five feet long. They have cloven hooves and create tracks similar, though more square, than white tailed deer.

Feral swine have long been an ecological and economic disaster in much of the American South. From the Carolinas to Texas, as well as California, feral swine are firmly established and the evidence of their presence is everywhere, in forests with almost no understory remaining, in agricultural fields with damaged crops, and in residential areas with ruined gardens. Populations are growing in Northern states as well and may be aided by climate change as winters become milder. The US Department of Agriculture estimates the national economic cost of feral swine damage at 1.5 billion dollars annually and growing.

Feral swine were among the first invasive species brought to the Americas in the 1500s by Europeans. Conquistadores herded swine as a food source on their meandering journey through what are today America’s southern states. In recent years, as pot-bellied pigs have become popular pets, there has been an increase of former pets abandoned by irresponsible owners. One mating pair of escaped pigs can quickly populate an area. Like other invasive species, swine mature quickly and are able to reproduce as early as six months of age. Since they can breed year-round and have two litters of four to one dozen piglets each, their populations can double in size in four months. This creates the necessity for continued vigilance to ensure wild populations do not form. As pigs are omnivores, both wild plant and animal populations are at risk.

Photo: USDA APHIS Wildlife Services

Strategic feral swine prevention in Maryland is a joint effort by the US and Maryland Departments of Agriculture and the Maryland Department of Natural Resources. Collectively these agencies work to correct inadequate hog farm containment, locate and remove free-ranging pigs, and educate the public about how much Maryland stands to lose if feral swine become established here.

Marylanders are encouraged to shoot pigs that are determined to be wild and not associated with a nearby owner. If you find a hog you should report it to Maryland Department Wildlife and Heritage Service (410-260-8539) or jonathan.mcknight@maryland.gov of Natural Resources or US Department of Agriculture (866-487-3297).